<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .c1,.c3{
            height: 50px;
            width: 50px;
            background-color: red;

        }
        .c2{
            height: 50px;
            width: 50px;
            background-color: green;
            /*display: none;*/   /* 隐藏标签,不占原来的位置 */
            visibility: hidden;  /* 原来的位置还占着 */
        }
    </style>
</head>
<body>

<div class="c1"></div>
<div class="c2"></div>
<div class="c3"></div>


</body>
</html>